Moved documentation out to pdb.doc file. Moved class Cmd out to module cmd.py. Rewrote implementation of stack trace to incorporate traceback objects.
Moved documentation out to pdb.doc file.
Moved class Cmd out to module cmd.py.
Rewrote implementation of stack trace to incorporate traceback objects.

sk-/python2.7-type-annotator,sk-/python2.7-type-annotator,sk-/python2.7-type-annotator